diff --git a/code/modules/surgery/organs/lungs.dm b/code/modules/surgery/organs/lungs.dm
index c455799f5a..3d5d2b34bd 100644
--- a/code/modules/surgery/organs/lungs.dm
+++ b/code/modules/surgery/organs/lungs.dm
@@ -297,7 +297,7 @@
 			if(miasma_pp > MINIMUM_MOLES_DELTA_TO_MOVE)
 
 				//Miasma sickness
-				if(prob(0.5 * miasma_pp))
+				if(prob(0.05 * miasma_pp))
 					var/datum/disease/advance/miasma_disease = new /datum/disease/advance/random(2,3)
 					miasma_disease.name = "Unknown"
 					miasma_disease.try_infect(owner)